In the last decade, the world of data management has been revolutionised by the influence of universally available distributed and mobile information technology. The jump from desktop and laptop to the smartphone has been a major driver, and the current explosive growth of the internet of things is another. Big data analytics is no longer only a buzzword in computer science, but transcends all levels of business, politics, and society.

Trust, transparency and traceability (or nontraceability) are important in online transactions, which may involve banks, notaries, public administrations, trusted-third-parties, witnesses and others. Even long before the internet, people in ancient civilizations used tools to create a permanent trace, such as a public (or private) ledger: Assyrian people used tablets and Incas used khipus, for instance.

Blockchains can be defined as immutable decentralised ledgers for recording transactions that - depending on the system - are to various degrees resilient to malicious behaviour. Blockchain peers maintain copies of the ledger that consists of groups of transactions (blocks) linked together into a hash-chain. This effectively establishes total order among blocks and, consequently across transactions. Transactions have in recent years evolved to allow the execution of arbitrary logic, also known as smart contracts. In principle, a smart-contract is an application that operates on top of blockchain, which uses the underlying ordering of transactions (i.e., consensus) to maintain consistency of smart contract execution results across peers, now also referred to as execution replicas.

by Daniel Augot (Inria, École polytechnique, and Université Paris-Saclay), Hervé Chabanne (OT-Morpho and Telecom Paristech) and William George (École polytechnique and Université Paris-Saclay)

We propose a way for users to obtain assured identities based on face-to-face proofing that can then be validated against a record on Bitcoin's blockchain. We obtain anonymity for users by making use of a scheme of Brands to store a commitment against which one can perform zero-knowledge proofs of identity and also enforce the confidentiality of the underlying data by letting users control a secret of their own. This way, users can gain access to services thanks to the identity records of our proposal.

We introduce SpaceMint, a cryptocurrency that replaces energy-intensive computation underlying most of today’s cryptocurrencies by “proof of space”. Once set up, SpaceMint consumes very little energy, which will motivate regular users to participate in the mining process thereby truly decentralizing control over the currency.

The Communication Systems Group (CSG) of the University of Zürich has been exploring the use of blockchains in several application areas. The work concluded that for practical use, Bitcoin transactions should be gathered in a batch.

Bitcoin’s distributed ledger is an innovative way of solving the double spending problem in a decentralised system. However, it causes incompressible transaction delays and incentivises consolidation of mining power. We ask, is it possible to eliminate these problems without losing the decentralised principles that Bitcoin was built on?

Secure Execution of Smart Contracts (SESC) aims to identify and analyse security aspects of smart contracts and the platforms on which they execute from a holistic viewpoint. We focus on the long-term sustainability and security of smart contract infrastructures.

The advent of Bitcoin as a decentralised cryptocurrency has a fundamental impact on both practical applications and scientific research, reaching well beyond its immediate use-case as a form of currency. Many concepts that previously needed to rely on a trusted third party now become feasible as decentralised implementations, thanks to Bitcoin's underlying blockchain technology.

Smart contracts are a proposed mechanism to help maintain consistency among data and transactions. They are automatically triggered by the conduct of a transaction and they also function to safeguard transaction histories. A cascade of automatically initiated smart contracts could result in data errors and smart contracts interfering with one another, but correctness can be assured by means of model checking.

Blockchain technology offers huge potential to various industries and application areas. In a joint applied research project, Fraunhofer Institute for Applied Information Technology (FIT) together with Norddeutsche Landesbank (NORD/LB) identified (inter-company) workflow management as a promising application area and developed a Blockchain prototype for a documentary letter of credit in the international shipping business. In addition to the project’s explicit outcome – a Blockchain prototype and strategic support for Blockchain innovation management – the joint project revealed important insights into the technology’s applicability in the field.

Customisable proofs of work and memory hard functions are investigated by the SnT&CSC/CryptoLUX team at University of Luxembourg. Proofs-of-work (PoW) are at the core of most of the present day blockchains and cryptocurrencies. These are the tools that make large public distributed ledgers possible, since they replace the difficult to quantify and manage trust by hard to forge mathematical computations.

Current blockchain technology as used by Bitcoin [1] and others uses a consensus model to determine the head of the chain and lets divergent branches starve, causing information loss. Information loss can be problematic for alternative blockchains in which connectivity could be reduced for longer periods of time and a consensus model is infeasible.In order to support sparsely connected clusters of machines working on independent branches of a blockchain, divergent branches must be able to be merged with each other by a merging algorithm that carries the consensus of all parties involved.

Until recently, digitalisation in the public sector was characterised largely by making existing processes faster or more efficient. Blockchain instead is challenging established public structures. Currently publically controlled functions for interaction could be organised completely privately, which requires a repositioning of the state. At the same time, Blockchain provides a technological approach that can be used by the public sector itself to improve transparency and trust.

The use of distributed ledgers (DL) in healthcare applications presents the opportunity to create new interoperable and secure environments, from which both medical professionals and patients can benefit.

As the notion of circular economy gains momentum, intelligent assets increasingly form the backbone of sustainable ecosystems. Although these assets can supply the necessary knowledge for fueling the value drivers of a circular economy, the generated value will be significantly amplified by allowing third parties to manage them and profit from better asset utilisation. However, for an ever-changing networked environment consisting of numerous assets, ownership needs to be dynamic, granular and adaptable in order to maximise gains. Blockchain-based mechanisms can effectively serve this need by enabling transfer of asset ownership directly between parties participating in the circular economy while introducing trust, efficiency and automation in asset exchange contracts.

Blockchain technology is relatively young, although the underlying cryptographic mechanisms have been known in computer science for some time. At NTNU we are interested in questions such as “Will blockchain and smart contracts make society better? Does this mean that we must have trust in the code, and not in humans? Could Blockchain technology be used as a powerful cyber weapon?”

The ability to use identities in many different digital contexts is vital for doing electronic business transactions. Such identities are hard to come by, in particular when the transaction involves international parties that do not necessarily trust each other (yet). The Dutch Techruption project has taken on the challenge of specifying a self-sovereign identity framework (SSIF) that aims to solve this problem, and to build demonstrators that show its practical use, for businesses, consumers and governments. Blockchain technologies are used for critical parts, such as storing commitments to attestations and revocation events.

We defined a distributed access control system on top of blockchain technology. The underlying idea is to properly represent the access rights of the subjects in the blockchain in order to easily allow their enforcement at access request time. By leveraging blockchain advantages we can add new desired properties, such as auditability, to the access control system. To prove the feasibility and validate the proposed approach we developed a proof of concept implementation and performed some relevant experiments.

The new EU General Data Protection Regulation (GDPR) [1][L1], which will come into effect in 2018, demands transparency as one of the main principles for the collection, processing, storing and transfer of personal data. Transparency ensures that individuals can enforce their legal rights: to withdraw consent for their personal data to be processed or to request that their data are erased. At the Luxembourg Institute of Science and Technology we filed a patent, based on blockchain technology, that guarantees transparency in the context of files that are exchanged in a shared data pool. It guarantees that access by partners to specific files can be traced without a central entity.

Earlier this year, as part of the government’s Digital Agenda, the top-level ICT Team set up by the Dutch Ministry of Economic Affairs instigated the formation of a National Blockchain Coalition. This coalition is a joint initiative of over 20 organisations – including Centrum Wiskunde & Informatica (CWI) – active in government and research, as well as the financial, health, logistics, and energy sectors. With this NBC initiative, the Netherlands aims to become one of the international leaders in blockchain development and applications.

Blockchain is considered to be enabling technology that is going beyond the Bitcoin crypto currency. It replaces centralised transaction management by the distribution of transactions across a network of nodes with different methods for consensus finding. This major change of governance may change sectors of our societies far beyond digital currencies. Fraunhofer FIT established a Blockchain Lab in 2016 in order to explore its impact. It will serve as an experience lab for technical components, implementation platforms, application prototypes and blueprints for novel governance, process, and business models.